Pengxuan “Dean” Diao filed a lawsuit against the gas company after an explosion four years ago left him with severe burns and brain damage, City News Service reported.

Diao, 26, was living in a converted garage in San Gabriel when a gas company employee opened a valve that filled the garage with gas. After Diao lit a cigarette, the room ignited, according to court filings.

Because of the explosion, Diao has limited memory and will likely experience dementia by the time he’s 50, Rahul Ravipudi, one of Diao’s attorneys, said during closing arguments.

The gas company acknowledged liability before the trial but, in turn, sued Diao’s landlords, Richard Liu and Joanna Cheung, and another tenant.

Jurors said the gas company must pay about $18 million and Diao’s landlords must pay about $2 million. The other tenant was absolved of liability.

Denise King, a spokeswoman for the gas company, reiterated the company’s condolences to Diao but said the company disagreed with the size of the award.

An attorney for Liu and Cheung did not immediately respond to an after-hours call and email seeking comment.